Each semester includes law (Article 33 of Law 4009/11) obligatory for at least 13 full weeks of teaching. The number of weeks for the examination is determined by the regulations of the institution. If for any reason this minimum number of teaching weeks is not completed in a course, this lesson is considered as not taught and is not allowed to be examined. In the case of an examination of a non-taught course, the examination is considered void and the grade cannot be counted for the diploma. Extension of the duration of a semester is only allowed in exceptional cases in order to complete the required minimum number of teaching weeks, it cannot exceed two weeks and is made by decision of the Rector at the proposal of the School's Quaesture (par. 6, article 33 of law 4009/2011).